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Algae frustration

I shock my pool last week to a FC level of 30ppm because of the beginnings of an algae problem on the floor of the pool. After the water cleared up, and I passed the OCLT, and the CC's dropped to 0, I started to let the FC level drop back to normal. Today (a week later) FC level is finally 9.5. It's the first day that FC gotten close to the normal range since shocking. Just for good measure, I did the OCLT last night to this morning, and I only lost 0.5 overnight. Yesterday, the water looked great. However, this morning the water still looks clear, but I'm starting to get the same little green algae blooms and trails on the floor of the pool that prompted me to shock last week. I'm frustrated because my test results from this morning indicate fairly normal. I have been brushing the pool all week, with light swimming. We have had heavy rain for the last two days that added 2 inches of water to my pool. Here's my morning test results:

FC-9.5
CC-0
TC-9.5
TA-140
PH-8.0
CYA-52
CH-170

I know the PH and TA are a little high. I wasn't able to accurately monitor the PH for the last week since FC was above 10. I'm going to lower the PH this afternoon, and I'm considering shocking again Any ideas?

Re: Algae frustration

Hey beechjetdriver,

Since no one else has yet, I'll chime in. I read and reread you post a couple of times and it seems that you have done good job of shocking (if not excessive, you were close to mustard algae shock level for 52 ppm CYA). How do you get your test numbers? Any chance your CYA test is reading low? Also, when you started shocking, where was your ph? I have read on the board here that shocking is most effective at lower ph (I have seen 7.2 recommended).

Re: Algae frustration

Testing was done with my TF100 test kit this morning. CYA of 52 was a ballpark. The black dot disappeared between 50-60, but on the lower end of that. PH when I shocked last week was 7.6. I brushed again this morning after I posted, and there has been no reformation of algae since then, and the water still looks clear, however, it's only been 2 hours. When I brush, there is a greenish brown dust that is stirred up, then dissolves in the water. At no point does it turn the water green or cloudy. I'm fairly certain it's not just dirt because it's an obvious green/yellow color (unless I'm color blind This morning there was also some green/yellow trails where the floor meets the walls. I'm thinking about shocking again. Should I lower the PH down to 7.2 before I shock? I guess I'm at a loss on what to do. Thanks for all your suggestions!

Re: Algae frustration

You might have poor bottom circulation. If you don't have multiple returns or none are pointed downward, you might try pointing one diagonally downward to get a circular swirling circulation pattern to help get chlorine to the bottom of the pool.

Is your pool vinyl a blue color? If so, then yellow pollen against the blue background can sometimes look green so you might have pollen instead. You can try a skimmer sock to see if it picks up pollen before it gets water-logged and falls to the bottom.

Re: Algae frustration

Update: I brought the FC up to shock level 16 (not mustard algae shock level) yesterday and brushed. I didn't have time to to the OCLT last night, but it has passed the last couple nights, so I assume it would pass again. This morning there is still some green trails and splotches on the pool floor. I thought about it being pollen yesterday too, especially since it's still showing up at shock level. I may also have poor circulation. There is only one return and I've tried pointing it diagonal and downward. The people that lived here before me dug out the middle of the pool to make it a little deeper (5ft or so). I do have a skimmer sock installed that does collect some stuff, but it's hard to say if it's pollen or dirt. If it's pollen I should be able to vacuum to waste and it won't come back, correct? If so, maybe I'll try that today and if that doesn't work, I'll go to mustard algae shock level tomorrow. Thoughts?

Re: Algae frustration

hmmmm, well just to let you know, I fight pollen everyday, I can vacuum and it's back the very next day. There is no avoiding it because I'm surrounded by woods and trees and all kinds of plants. I determined it was pollen when I took off my skimmer sock and let it dry with the stuff still on there, once it was dry it kind of resembled dryer lint. I could vacuum to waste but it would be a daily process and really not worth it. I collects in the divits and wrinkles in my liner, I just throw my cleaner in and let it do it's thing until the next day.

Re: Algae frustration

I recently encountered something like this on a job. In addition to being a Los Angeles house cleaning company, we also offer general property maintenance services including pool treatments to our clients. I tried all sorts of chemicals to clear the water. We ended up having to drain the pool and scrub it clean.

Re: Algae frustration

How long do you run the pump every day? Sometimes when you brush or vacuum the pool the fine dirt goes back into suspension and when the pump has been off for a while it falls back to the floor of the pool.

Re: Algae frustration

I run the pump 12 hrs/day. I had to go out of town for work for 5 days. Before I left, I brought the pool to mustard algae shock level, brushed and covered it with the solar cover. I'm letting the pump run 24/7 for the days I'm gone. I guess we will see what it looks like when I get back.

Re: Algae frustration

Update: I just got back from my 5 day trip. The entire bottom of the pool was covered with a green/yellow dust, with some yellow and brown dirt patches spread around the floor (nothing on the walls). Before I left on my trip, I had shocked to 35ppm, brushed, covered with the solar cover, and let the pump run 24/7. While I was gone, half of the solar cover blew off the pool due to a storm. Once I got home, I immediately brushed the pool, and tested the water. When I brushed it, you could see blue path marks from where I brushed, and green where I hadn't brushed. After brushing, the water turned a slight green tint, but cleared up some after an hour. It still isn't as blue as it should be. I'm going to do an OCLT tonight. Here's my test results from the TF100:

FC-15
CC-0
TC-15
PH-8.1 (high from shock)
TA-140
CYA-50

This is so frustrating, and I'm not sure what to do. I'm thinking I should bring it back to mustard shock level this afternoon, and keep it there for the weekend, brushing every day. I also have some left over phosphate remover (I know, I know...) from before I switched to the BBB method. I'm thinking about adding that too since I have it on hand. Any other ideas?

Re: Algae frustration

Your description is precisely what my pool looks like when I have inadequate chlorine levels and allow mustard algae to take hold. I haven't read through this whole thread but your description is so completely identical to what I see in my pool, I immediately think you have mustard algae.

Shock the Pool. Do so precisely by the directions in the article in pool school. A little brushing and that algae will go away quite easily if your Chlorine is adequate. Keep in mind that your water is made up of H2O like the rest of us and that ADEQUATE chlorine levels held in the pool CONSTANTLY will, in fact, result in an algae free pool.

Don't worry too much about the OCLT until your pool is crystal clear and it has gone several days without any sign of algae. You are going through the reagents pretty quickly by doing that test so much and, while I LOVE selling refills, I think you are wasting some money.

5 days is too long to neglect the pool, IMO. It will be difficult to keep that pool clean with your work schedule.

You can add the phosphate remover to the pool or to the sink, the effect will be about the same!!